Just wanted to get some opinions on using these BUIS.



i have these on another ar i have. and like them a lot. but i am worried because of the front sitting on the gas block and the base being polymer. i would really like to use these as i have get a fairly hefty discount on them through work.

Polymer sights are not recommended for mounting to a railed gas block.

Since you won this rifle, I'm assuming you don't have much cash invested in it. If that is the case, take a little money and put a low profile gas block on it with a free float extended rail... that seems to be what you want, so why not just do it?

Believe it's mostly internet bs but then again if a rat smokes for 10 years it might get cancer. Polymer's pretty tough. Will the Magpul MBUS Gen 2 polymer front site melt if mounted to a rail on the gas block? : ar15

Seeing how a manufacturer (Magpul) warns against it, I wouldn't call it internet bs. They don't melt, as in leaving you a pool of melted plastic, but they can become brittle and cause a shift in POI with POA.

Also, the front sight asked about by the OP has been discontinued by the manufacturer... didn't have very good reviews either... I'm thinking that those two things together should be a good indicator of the quality of that particular sight.

It's called CYA. Had a Gen 1 on a DPMS railed gas block for a few years, probably around 2,000 rounds worth. No wear whatsoever and did not deviate due to expansion / contraction.

If they feel the need to C their A, then the possibility exists that the product will fail when used in that manner.

If you are shooting slowly or not doing mag dumps, it may be fine. However, I've seen reports on other forums where they did lose zero after being subjected to shooting that heated up the barrel. I've seen reports of them becoming brittle.

It's your money, do what you want to do... in this case, I tend to follow Magpul's advice that their product is not intended for use on the gas block.

Yes, there's always an exception.